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Biphytane

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Biphytane (or bisphytane) is a C40 isoprenoid that is composed of two phytanes linked together.[1] Biologically, they are derived from archaeal ether lipids and hence, it is considered to be a biomarker of archaea when detected.[2]

Biphytane
Names
IUPAC name
3,7,11,15,18,22,26,30-Octamethyldotriacontane
Identifiers
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chemical structure

Acyclic biphytane is formed by isoprene units bound by ether bonds with six isoprene units (or two phytanes) linked together by a head-to-head linkage.[3] The cyclic biphytanes contain one to three pentacyclic rings with the number of carbons remaining the same. The cyclic forms can be referred to with different notations. A few examples are listed below.

Notations for different forms of biphytane in literature
0 rings 1 rings 2 rings 3 rings Reference
Biphytane II Biphytane III Biphytane IV Biphytane V [2]
C40:0 C40:I C40:II C40:III [4]
Acyclic Monocyclic Dicyclic Tricyclic [5]

**in the process of updating the chembox chart with the chemical information (chemical structure, formula, IUPAC name, CAS #, structure, ... ) but need to figure out how to add the info to the sections..

Biological origin

Biphytane is a breakdown product of archaeal ether lipids, such as glycerol dialkyl glycerol tetraethers.[2] Therefore, along with phytane, acyclic and cyclic biphytanes are well established as biomarkers of archaea.[2]

The presence and number of rings in the compound can potentially serve as further indicators to specify the compound's biological origin. For instance, it has been reported that thermophiles increase the degree of cyclization with increasing growth temperatures.[6] Such addition of pentacyclic rings allows for a denser packaging of the membrane and thus a more thermally stable membrane.[6] However, it should be noted that cyclic biphytanes can also origniate from non-thermophilic crenarchaeota and in the marine environment.[6] For crenarchaeota, tricyclic biphytane is considered to be characteristic of its membrane lipids while the monocyclic form is generally the least abundant.[2]

In marine sediments, the acyclic biphytane is typically the most abundant, the monocyclic form is the least abundant, and bicyclic and tricyclic forms are observed in comparable amounts.[5]

Measurement techniques

When deriving from ether lipids, the ether bonds are first cleaved using hydrogen iodide (HI), boron trichloride (BCl3), or boron tribromide (BBr3) that produces alkyl halides. Then, the alkyl halides are either reduced to saturated hydrocarbons using HI/NaSCH3 or LiAlD4 or converted to methylthioesthers with NaSCH3. The obtained saturated or derivatized hydrocarbons can subsequently be separated and measured using standard GC/MS procedures.

Mass spectral fragment ions characteristic of (acyclic) biphytane. Blue lines mark the location of fragmentation and the associated numbers correspond to the resulting ion fragments' m/z values.

The diganostic mass spectral fragment ions for acyclic biphytane are m/z 197, 259, 267, 323, 383, 393, and 463.[3] The cyclic biphytanes yield different mass spectral fragment ions making the differentiation of the forms of biphytanes present in a sample possible.[7]

References

  1. ^ Heathcock, Clayton H.; Finkelstein, Bruce L.; Aoki, Tadashi; Poulter, C. Dale (1985-08-30). "Stereostructure of the Archaebacterial C 40 Diol". Science. 229 (4716): 862–864. doi:10.1126/science.3927485. ISSN 0036-8075.
  2. ^ a b c d e Schouten, Stefan; Wakeham, Stuart G; Damsté, Jaap S. Sinninghe (2001-10-01). "Evidence for anaerobic methane oxidation by archaea in euxinic waters of the Black Sea". Organic Geochemistry. 32 (10): 1277–1281. doi:10.1016/S0146-6380(01)00110-3. ISSN 0146-6380.
  3. ^ a b Peters, Kenneth E.; Walters, Clifford C., "Biomarker: Aliphatic", Encyclopedia of Earth Science, Dordrecht: Kluwer Academic Publishers, pp. 31–33, retrieved 2023-04-28
  4. ^ Pape, Thomas; Hoffmann, Friederike; Quéric, Nadia-Valérie; von Juterzenka, Karen; Reitner, Joachim; Michaelis, Walter (2006-02-02). "Dense populations of Archaea associated with the demosponge Tentorium semisuberites Schmidt, 1870 from Arctic deep-waters". Polar Biology. 29 (8): 662–667. doi:10.1007/s00300-005-0103-4. ISSN 0722-4060.
  5. ^ a b Pancost, Richard D.; Coleman, Joanna M.; Love, Gordon D.; Chatzi, Athina; Bouloubassi, Ioanna; Snape, Colin E. (2008-09). "Kerogen-bound glycerol dialkyl tetraether lipids released by hydropyrolysis of marine sediments: A bias against incorporation of sedimentary organisms?". Organic Geochemistry. 39 (9): 1359–1371. doi:10.1016/j.orggeochem.2008.05.002. {{cite journal}}: Check date values in: |date= (help)
  6. ^ a b c Damsté, Jaap S.Sinninghe; Schouten, Stefan; Hopmans, Ellen C.; van Duin, Adri C.T.; Geenevasen, Jan A.J. (2002-10). "Crenarchaeol". Journal of Lipid Research. 43 (10): 1641–1651. doi:10.1194/jlr.M200148-JLR200. {{cite journal}}: Check date values in: |date= (help)CS1 maint: unflagged free DOI (link)
  7. ^ Saito, Ryosuke; Kaiho, Kunio; Oba, Masahiro; Tong, Jinnan; Chen, Zhong-Qiang; Tian, Li; Takahashi, Satoshi; Fujibayashi, Megumu (2017-09-01). "Tentative identification of diagenetic products of cyclic biphytanes in sedimentary rocks from the uppermost Permian and Lower Triassic". Organic Geochemistry. 111: 144–153. doi:10.1016/j.orggeochem.2017.04.013. ISSN 0146-6380.
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